Git gc & Maintenance
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git count-objects -v
git gc [--prune=now]What is Git Garbage Collection?
As you modify and delete files, Git accumulates loose, unreferenced objects and legacy history fragments. Garbage collection compresses these files into packed files, optimizing repository size and speed.
Example: What is Git Garbage Collection?
git count-objects -vRunning git gc
git gc bundles loose objects into compressed pack files and removes objects that are no longer referenced by anything, shrinking the .git directory and speeding up operations that scan history — most repositories never need to run it manually since Git triggers it automatically past certain thresholds.
Example: Running git gc
git gcPruning Loose Objects
Objects left over from a discarded commit, an aborted rebase, or a deleted branch stick around until they're pruned — git prune removes any object no longer reachable from a branch, tag, or the reflog, freeing the disk space they were taking up.
Example: Pruning Loose Objects
git pruneChecking Repository Health
git fsck walks every object in the repository's database checking for corruption or dangling references (objects that exist but nothing points to), which is the tool to reach for if a repository starts behaving strangely and you suspect the underlying data itself is damaged.
Example: Checking Repository Health
git fsckAutomated Background Maintenance
Since Git 2.30, git maintenance can schedule background tasks — prefetching, incremental repacking, loose-object cleanup — to run periodically without you remembering to invoke gc yourself, keeping large, long-lived repositories fast without manual upkeep.
Example: Automated Background Maintenance
git maintenance start- Running
git gc --prune=nowand expecting to keep recoverable commits, when it removes unreferenced objects permanently. - Running
git gcoften out of habit, when Git already runs it automatically when needed. - Expecting
git gcto make the repository much smaller after committing large binaries, when the files remain in history.
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